“Authentication,” in general, is the process of determining that a person is who he or she claims to be. Airline travelers, for example, authenticate themselves at an airport by presenting to airline officials a photo-bearing document bearing the traveler's name, such as a driver's license or passport (a “certificate”), and the traveler's face (a “credential”), which can be matched with the photo on the document. In this example, an airline official checks the credential against the information on the “certificate” and, if it matches, the traveler is “authenticated” and allowed to board the airplane.
The notion of “authentication” is closely related to those of “authorization” and “accounting.” An entity is typically authenticated before being allowed to receive a service, whereas accounting is performed after the service is provided.
Public key infrastructure (PKI) is a security architecture that has been developed to provide an increased level of confidence for exchanging information electronically over an insecure network. A PKI can include many different elements, but generally means the methods, techniques, and devices that together provide a secure infrastructure. PKIs can be used to authenticate the sender or recipient of electronic information and/or authenticate that the content of an electronic document or message has not been deliberately altered or otherwise modified. Generally, a PKI provides security by using a mathematical technique called public-key cryptography. Public-key cryptography uses a pair of mathematically related cryptographic keys, referred to as the “private key” (or “secret key”) and the “public key.” If one key is used to encrypt information, then only the related key can decrypt that information. If you know one of the keys, you cannot easily calculate what the other one is. As their names indicate, the private key is intended to be associated uniquely with one user and kept secret. The public key may be freely distributed and known to anyone.
Public-key encryption may be used to send information confidentially. For example, a sender may encrypt a message with the recipient's public key, which the sender has received from the recipient or obtained from a public directory. The recipient may then use his private key to decrypt the message.
“Digital certificates” and a “certificate authority” (CA) may be used to authenticate the identity of the entity associated with the public/private key pair. A CA is a trusted individual or organization (public or private) that issues, manages and revokes digital certificates. Although some applications, such as PGP, allow users to generate digital certificates themselves, a more “trusted” digital certificate may be obtained from a bona fide CA.
The CA may generate the public/private key pair in the digital certificate or sign the public key of a requester (after the CA verifies the identity of the requester). The CA verifies the credentials provided by the certificate requester and, upon confirming the requester's identity, digitally signs the digital certificate with the CA's private key.
A digitally-signed message or certificate may be authenticated by determining if the digital signature on the message or certificate is valid. When sending a signed message, the sender may also send his public key, alone or embodied in a digital certificate. A signed certificate will also indicate the identity of the CA that signed the digital certificate. The recipient of a digitally signed message or certificate may use the public key associated with the signer, as well as other information in the digital certificate, to determine if the signature is valid.
In conventional electronic authentication systems, authentication of digital certificates often requires a network connection between an authentication server (such as the server of the CA that issued a digital certificate) and the individual wishing to authenticate a document (or the device node where the individual is located). Typically, to authenticate a digital certificate, a user or a device using conventional authentication services, an entity must connect across a network to an authentication server, which then performs authentication at the network server. Faulty, disconnected or unsecured network and server conditions, such as a network or server under denial-of-service attacks, may undesirably result in defective or failed authentication.
There is thus a general need in the art for an authentication device and method overcoming at least the aforementioned shortcomings in the art. A particular need exists in the art for an authentication device and method overcoming disadvantages in authentication over networks under faulty network and server conditions.